The shaping of curved sheet metal components, especially spherically or three-dimensionally curved sheet metal components, such as planking elements for aircraft, requires that the support points for the sheet metal pieces are exactly positioned during the molding or shaping. By "exactly positioned" in this context is meant that the support points must be located along a three-dimensional configuration that conforms exactly to the intended configuration of the work pieces in order to avoid local deformations that do not conform to the intended configuration of the work piece in a three-dimensional coordinate system.
German Patent Publication (DE) 3,126,720 C2 discloses clamping elements which hold a work piece by applying reduced pressure or suction to the clamping element. Such conventional clamping elements comprise a support that is vertically adjustable. The support holds a suction cup element in a hemispherical shell or cavity of the support in a pivotable manner. Thus, a suction cup plane can be adjusted to different angles relative to a horizontal plane. The support is equipped with connection nipples for the supply, either of pressurized air, or to a suction generator for producing reduced pressure in the suction cup.
The conventional holding or clamping device is limited in the angular adjustability of the position of the suction cups so that it is difficult to hold work pieces of a complicated, three-dimensionally curved configuration.